Arrangements for stopping electrically operated sewing or other machines



March 9 K. WINZ 2,876,407

ARRANGEMENTS FOR STOPPING ELECTRICALLY OPERATED SEWING OR OTHER MACHINESFiled July 29, 1954 5 Sheets-meet 1 FIG- 7 March 1959 K. wlNz 2,876,407

ARRANGEMENTS FOR STOPPING ELECTRICALLY OPERATED SEWING OR OTHER MACHINESFiled Juiy 29, 1954 s Sheets-Sheet 2 INVENTOR.

IrML w Z BY my/m March 3, 1959 w Z I 2,876,407

ARRANGEMENTS FOR STOPPING ELECTRICALLY OPERATED SEWING OR OTHER MACHINESFiled July 29. 1954 3 Sheets-Sheet 5 Fig. 3

INVENTOR.

United States Patent ARRANGEMENTS FOR STOPPING ELECTRICALLY OPERATEDSEWING OR OTHER MACHINES Karl Winz, Kaiserslautern, Germany, assignor toG. M.

Pfaff A.-G., Kaiserslautern, Pfalz, Germany, a corporation of GermanyApplication July 29, 1954, Serial No. 446,517

Claims priority, application Germany August 3, 1953 3 Claims. (Cl.318--269) The present invention relates to an arrangement onelectrically driven sewing or other machines for stopping the needle rodor other element thereof in pre-determined positions.

The invention primarily consists of a relay arrangement energised in theoff-position of a regulator or the starter for the electric drivingmotor from a switch associated therewith and which is supplied withcurrent and operates in conjunction with a control switch influenceddirectly or indirectly by the needle rod or other positively moved partof the sewing or the like machine, mainly by mechanical means. Theswitching parts of the said control switch are at the same timeconnected with the positively moved parts of the sewing or the likemachine in such a manner that their position corresponds with apre-determined position of the stitch making tool or other element ofthe machine.

In order to ensure a regular switching sequence it is desirable to takemeasures which delay the demand of the relay arrangement and allow theswitching operation of the latter to become effective when the electricdrive of the sewing or other machine has either completely or nearlycome to a standstill. This may, for example be accomplished by designingthe control relay as a time delay relay. For the same purpose anadditional switching element with a retarded action, such as for examplea supplementary relay, may be provided.

It has further been found expedient to insert the control switch inseries with a switching element, designed in such a manner thatpre-selection of different possible switch positions may be achieved,the particular preselected switching position corresponding, at any timewith the desired definite stopping position for the stitch making toolor other element of the machine.

An object of the invention is also to provide improvements in the relayarrangements which take into account the particular electrical drive ofthe sewing or other machine. As a rule the drive of a sewing machine iseffected either by means of a motor driving through a clutch or by meansof a motor which drives the machine directly. With the first type ofdrive a coupling disc is adapted to be driven by a magnetic engagingdisc fixed on the shaft of the drive motor and is adapted to be brakedby an immovable magnetic braking disc located on its opposite side.

With such drives the present invention provides for the control of thecoil of the magnetic engaging disc. The coil of the magnetic brake discis then included in another circuit which, with the aid of the relayarrangement can be interrupted. In such cases it has furthermore beenproved advantageous to provide regulatable resistance betweent the coilsof the magnetic engaging disc and the said relay arrangement whichpermits the said coil to receive controlled current.

When the sewing or other machine is driven by means of a directlycoupled motor which in known manner is fitted with a mechanicaloperating brake, it is preferable to place the relay arrangement of thepresent invention in the circuit of the, releasing magnet for the brake.In such case it is advantageous to use a switch arrangement whichsupplies the motor with increased current when the brake is released byshunting a part of the resistance connected in series with the motor.

The invention is more particularly described with reference to theaccompanying diagrammatic drawings, by way of example, in which:

Fig. 1 is a perspective view of a sewing machine fitted with the controlarrangement.

Fig. 2 is a circuit diagram suitable for adoption when a coupling motoris used to drive the sewing machine.

Fig. 3 is a circuit diagram of a suitable arrangement when using adirectly coupled motor for driving the sewing machine.

Fig. 1 shows a driving motor 1 of the usual type which is fixedunderneath the sewing machine table 1. On the drive side of the motorthere is provided in known manner a clutch which consists of a couplingdisc 10, placed between an electrically operated magnetic disc 4arranged on the shaft of the motor for rotation therewith and astationary magnetic disc 7. The coupling disc 10 is rotatable and isconnected with the driving pulley 10a of the machine around which passesthe usual driving belt 10b while the magnetic disc 4 functions as anengaging medium.

When the electric circuit of the engaging magnetic disc 4 is closed bythe actuation of a switch device 14 (Fig. 2), then disc 4 will causerotation of the coupling disc 10 along with it and set the disc 10 inmotion. When however, by the corresponding movement of a switch 15, thecircuit of the magnetic braking disc 7 is closed, said disc 7 attractsthe coupling disc 10 and by a braking effort thereon, brings it to astandstill.

A switchbox 2, fixed beneath the sewing machine table 1' accommodates inaddition to other switching gear a switch 2 which is at the same timeconstructed as an automatic cut-out. This switch serves as a control forthe whole switching arrangement. In the housing of the electricmotor 1 arectifier 3 is placed which as Figure 2 shows supplies the switchingarrangement with the required direct current.

The rectifier 3 draws current from the stator coil of the motor 1. Thestator coil thereby acts as an autotransformer.

The arrangement of relays in both examples of circuits illustrated inthe drawings consists of three relays, which are housed in the switchbox2'.

The electric current to the switchgear in the switchbox may be suppliedin known manner by means of contact media, not shown for example throughknifeshaped contact strips which may be inserted between springy orspringloaded contact elements.

As shown in the circuit diagram of Fig. 2, there is provided a statorwinding for the motor 1 which is arranged in Y (star) connection, andthe three ends of the coils of which are connected in a conventionalmanner to a network SSS. The switching arrangement for the motor mayconsist, for instance, of a three-pole switch (not shown). =l

During the operation of the sewing machine, the motor 1 is running allthe time. The operator will connect the sewing machine to the motor 1 ordisconnect it therefrom by means of the magnetic clutch arrangementreferred to in the foregoing. The principle of such a clutch arrangementis well-known, as evidenced by the German patent to Rotter, No.53,879/1890. To drive the sewing machine, the operator will cause themagnetic disc 4 to be energized so that the disc 4 will turn thecoupling disc 10 to run the sewing machine. The energizing circuit forthe magnetic revolving disc 4 is-as follows;

marc es A lead 100 taps one of the windings or coils of the stator ofthe motor 1. Theswitch 2 is in series with the lead 100; as previouslymentioned, the switch 2 may be constructed as an automatic cut-offsafetyswitch. A lead 101 connects the switch 2 with the rectifier 3, andanother lead 102 connects the rectifier 3 with a brush terminal 5.Between the brush terminal 5 and another brush 6, the current is carriedby the magnetic disc 4. A lead 103 connects the brush 6 with a terminal104, and a lead 105 connects the terminal 104 with a terminal 13 of aregulator 11. A sliding contact 14 engages the regulator 11, and a lead106 interconnects the sliding contact 14 with a terminal 12. A lead 114connects the terminal 12 with a terminal 115, and a lead 107 connectsthe terminal 115 with the neutral point of the \'-connection of thestator winding of the motor 1, thereby completing the energizing circuitfor the magnetic disc 4.

By moving the sliding contact 14 along the regulator 11, there can beregulated the current supplied to the magnetic disc 4, so that therebythere can be controlled whether the sewing machine is driven fast orslow. If the energization of the magnetic disc 4 is reduced below apermissible minimum, by movement of the sliding contact 14 towards theright, the maximum resistance of the regulator 11 (near the positionshown in Fig. 2), the disc 4 will practically become tie-energized. Inthis position (slightly to the right of the position shown in Fig. 2),the sliding contact 14 will close the switch 15. Closure of the switch15 causes energizationof the stationary magnetic brake disc 7, in thefollowing circuit:

(II) Electric circuit. for energizing magnetic brake disc 7 (Fig. 2)

The brush terminal 5 is connected to a tap-off point of the stator.winding of the motor 1, as previously described in the circuit (I) forthe magnetic disc 4. A lead 108 connects the brush terminal 5 with abrush terminal 8. Between the brush terminal 8 and a brush 9, thecurrentis carried by the brake disc 7. A lead 109 connects the brush 9 with acontact 32 of a control relay 27. A movable contact 31 of the relay 27(in the position of the relay 27 shown in Fig. 2) interconnects thecontact 32 with an opposite contact 30. 'Two leads 110 and 112 in seriesconnect the contact 30 with one terminal 17 of the switch 15, and a lead113 connects the other terminal 16 of the switch 15 with the previouslymentioned terminal 12 of the regulator 11, the leads 114 and 107completing the circuit of the neutral point of the stator winding of themotor 1.

Thus, when the switch 15 is closed by impact of the sliding contact 14,the brake disc 7 will be energized and will cause braking of thecoupling disc and therebyof the sewing machine. At the same tirne, therewill be energized a time delay relay 18 in the following circuit:

(III) Electric circuit for energizing the time delay relay 1'8 A lead116 connects the brush terminal 5 with a terminal 117 of an auxiliaryrelay 22, and a lead 118 interconnects the terminal 117 with a terminal119 ofthe relay 18. From the terminal 119 the current is conducted to aterminal 20, and from there through the coil or winding of the relay 18to a terminal 19. A lead 120 connects the terminal 19 with a terminal111 which is interconnected between the leads 110 and 112 of thepreviously described circuit (11) of the magnetic brake disc 7, the lead112, the switch 15, and the leads 113, 114 and 107 completing thecircuit to the neutral point of-the stator windingof-the motor 1. Therelay 18 operates a movable contact 121 for opening and closingtheelectric connection between the contact 19 and an opposite contact 21.

The relay 1 8 actsunder a time delay, so that when the aforedescribedcircuit (Ill) is closed, the relay 18 will close the movable contact 121only after the lapse of a predetermined time interval. The contact 121is normally open, and is closed only-after said time interval when therelay 18 has been energized. The closure of the contact 121 willestablish the connection between the terminals 19 and 21 and close thecircuit for an auxiliary relay 22 as follows:

(IV) Electric circuit for-energizing. the-auxiliary relay 22 Currentwill flow from the terminal 117 (to which point it is carried aspreviously described by the leads 100, 101, 102 and 116) to a terminal24, and from there through the windings of the relay 22 to a terminal23. A lead 122 interconnects the terminals 23 and 21, and the contact121 when the relay 18 is closed interconnects the terminals 21 and 19.The connection between the terminal 19 and the stator windings of themotor 1 complete the circuit comprising the previously describedelements including the leads 120, 112, the switch 15, and the leads 113,114 and 107. '7

The auxiliary relay 22 is so arranged that its armature will be operatedonly once upon energization of its coil. The armature of the relay 22carries a movable contact 123. When the relay 22 is energized, themovable contact 123 will bridge the space between two terminals 25 and26 and will thereby close the circuit of the control relay 27, asfollows:

(V) Initial energizing electric circuit for the control relay 27 Theconnection between the stator winding of the motor 1 and the terminal119 of the relay 18 is as previously described, and includes the leads100, 101, 102, the terminal Send the leads 116 and 118. A lead 124connects the terminal 119 with a terminal 29 and the coil of the controlrelay 27. The coil or winding of the relay 27 connects the terminal 29with a second terminal 28. A lead 125 connects the terminal 28 with theterminal 26 of the auxiliary relay 22. When the auxiliary relay 22 isenergized, the movable contact 123 connects the terminal 26 with theterminal 25. A lead 126 connects the terminal 25 with a terminal 127,and a lead 128 connects the terminal 127 with an intermediate terminalthat is disposed between the leads 114 and 107. The lead 107 completesthe circuit.

When the control relay 27 is energized by this circuit (V), its armaturewill be moved to the left in (Fig. 2, as indicated by the arrow depictedon the armature). Thereby there will be moved to the left the movablecontacts 31, 33 and 36 that are carried by the armature of the relay27.Normally, the armature is in a rightward rest position (illustrated inFig. 2), so that the movable contact 31 normally is positioned acrossthe terminals 31 and 32 of the circuit (II) of the brake disc 7. Whenthe relay 27 is energized, however, the contacts 31, 33 and 36 will bemoved to the left and will in the following sequence cause the followingoperations:

Firstly, there will be opened by the contact 31 the connection betweenthe terminals 31 and 32, thereby deenergizing the circuit (II) of thebrake disc 7.

Secondly, the movable contact 33 will bridge two opposite terminals 34and 35.

Thirdly, and last in point of sequence, the movable contact 36 willbridge the gap between two opposite terminals 37 and 38.

When the movable contact 33 of the relay 27 closes the space between theterminals34 and 35, it establishes aghol ding circuit for the relay asfollows:

(VI) Electric holding circuit for the control relay 27 One of the statorwindings of the motor 1 is connected to the terminal 119 of the relay 18as previously ep ne t rn l as .0 .10 .0 .1 6an i T lead 124 connects theterminal 119 with the terminal 29 of the relay 27, and the coil of therelay 27 interconnects the terminals 28 and 29. A lead 129 connects theterminal 28 with the terminal 34. The movable contact 33, when the relay27 is energized, establishes the connection between the terminals 34 and35. A lead 130 connects the terminal 35 with a terminal 131. A lead 132connects the terminal 131 with a terminal 43. A movable first maincontact 47 of a control switch 42 is shown in Fig. 2 interconnecting theterminal 43 with an opposite terminal 45. A lead 134 connects theterminal 45 with the terminal 50 of a movable selector switch 49 that inFig. 2 is shown temporarily disposed between the terminal 50 and aterminal 52 to establish connection therebetween. The selector switch 49may be moved to make instead connection between the terminal 52 and aterminal 51 opposite relative to the terminal 50. A lead 135interconnects the terminal 52 with the terminal 127, and the leads 128and 127 complete the holding circuit to the center of the stator windingof the motor 1.

Between the terminals 131 and 52 there is provided a branch parallel tothat of the leads 132 and 134. The branch circuit includes a lead 133that interconnects the terminal 131 with a terminal 44. A second movablemain contact 48 of the control switch 42 is operable to establish aconnection between the terminal 44 and an opposite terminal 46. A lead136 connects the terminal 46 with the terminal 51 and, as previouslymentioned, the selector switch 49 may be moved to provide a connectionbetween the terminals 51 and 52.

. In Fig. 2, the contact 47 of the switch 42 is shown in closed positionand the selector switch 49 completing that branch, while the contact 48is shown in open position and the selector switch 49 disconnects thatbranch. The control switch 42 including its movable contacts 47 and 48is in positive connection with a cyclically moving element of the sewingmachine (such as with the needle bar or the transporting shaft, forinstance as shown in my co-pending application Serial No. 534,366, filedSeptember 14, 1955, now Patent No. 2,838,019). ment, both of the maincontacts 47 and 48 will be opened and closed.

Both parallel branches of the above described circuit part for thecontrol switch 42 are in series with the selector switch 49. 'Theselector switch 49 may be set by the operator either between theterminals 52 and 50 to be in series with the parallel branch of thecontact 47 (as shown in Fig. 2) or may be set between the terminals 52and 51 to be in series with the branch of the contact 48, instead. Theposition of the selector switch 49 determines the stop position of thesewing machine element such as the needle bar or-the like.

Shortly after the movable contact 33 connects the terminals 34 and 35,thereby closing the holding circuit (VI) for the control relay 27, therewill again be closed a circuit for energizing the revolving magneticdisc 4 bridging with the contact 36 of the relay 27 the ter' minals 37and 38, as follows:

(VII) Electric operating circuit for energizing the magnetic disc 4 Aportion of the circuit runs from a tap on a winding of the stator of themotor 1 to the brush 6, as previously described including the leads 100,101, and 102, the brush terminal 5, and the disc 4. The lead 103connects the brush 6 with a terminal 104 that is disposed on the lead105. The remaining circuit part is in parallel with the previouslydisclosed part of the lead 105, the regulater 11, and the leads 106, 114and 107, as follows: A lead 137 connects the terminal 104 with aterminal 41 of the resistor 39. A sliding contact 138 is adjustablypositionable along the resistor 39 for tapping. A flexible lead 139connects the sliding contact 138 with a During each complete cycle ofsuch ele-,

terminal 40. A lead 140 interconnects the terminals 40 and 38. When therelay 27 is energized, the movable contact 36 of the relay 27 bridgesthe gap between the terminals 38 and 37. A lead 141 interconnects theterminals 37 and 30. The circuit portion is completed by the leads and112, the switch 15, and the leads 113, 114 and 107 to the neutral pointof the windings of the stator 1.

By varying the position of the sliding contact 138 on the resistor 39there can be varied the degree of energization of the revolving magneticdisc 4. Normally, the oprator will maintain that energizationsuificiently large in order to assure revolving of the coupling disc 10.The sewing machine will run with a speed corresponding to the degree ofenergization of the magnetic disc 4 until that one of the two contacts47 and 48, of the control switch 49, is opened which is in series withthe selector switch 49 as the latter has been pre-set by the operator.In that instant, the holding circuit (VI) of the control relay 27 isinterrupted, and the armature of the relay 27 is retracted (into theposition shown in Fig. 2) including the movable contacts 31, 33 and 36thereof. During this retraction, the movable contact 36 will firstinterrupt the operating circuit (VII) for the magnetic disc 4 therebycausing de-energization of the disc 4; secondly, the contact 33 willopen the holding circuit (VI) of the relay 27 which has previously beeninterrupted; and lastly the contact 31 will reestablish the circuit ofthe magnetic brake disc 7 (II), whereby the brake disc 7 will brake thesewing machine by braking the coupling disc 10.

If it is desired to start the sewing machine again, the operator willmove the sliding contact 14 of the regulater 11 to the left (Fig. 2) toreactivate the circuit for energizing the magnetic disc 4 (I). By thisleftward movement of the sliding contact 14, there will be opened theswitch 15, interrupting the circuit for the brake disc 7 (II).

The purpose of the time delay relay 18 is to delay the energization ofthe control relay 27 until the sewing machine has been braked to a stopor nearly to a stop and the time interval of delay between theenergizing of the relays 18 and 27 must be so chosen as to be sufficientfor that purpose. The auxiliary relay 22 will respond only once uponenergization, and thereafter will again return its armature to the restposition, and during the return of the armature will interrupt thecircuit for the energizing of the relay 27 (V), so that the relay 27cannot respond more than once, and the relay 27 will then depend on itsholding circuit (VI) for continued energization until the holdingcircuit is interrupted. The time delay relay18 will be retracted whenthe switch 15 is opened. As shown schematically in Fig. 2, the controlswitch 42 with its contacts 47 and 48 is operated by an element of thesewing machine in a known manner.

The operation of the embodiment of Fig. 2 is as follows:

To start the sewing machine, the operator will move the sliding contact14 of the regulator 11 to the left (Fig. 2), reducing thereby theresistance of the energizing circuit (I) until the sewing machine willhave at tained a predetermined rotary speed. By increasing theenergization of the magnetic disc 4, the slippage between the magneticdisc 4 and the coupling disc 10 will be decreased until there issynchronous operation between these discs. The sewing machine is thenready for use, and will run in this manner until it is desired to stopit.

In order to arrest the sewing machine with the needle bar at aselectively predetermined position, the operator will move the slidingcontact 14 along the regulator 11 to the right (Fig. 2) until theresulting slippage occurringbetween the magnetic disc 4 and the couplingdisc 10 is so large that the coupling disc 10 will come to a standstill.Subsequently the brake disc 7 will be energized in an electric circuit(II), so that thereby the sew- 7 ingrnachinc-is positively arrested.During this operational-step, the retarding relay 18, the auxiliaryrelay 22, and the-control: relay 27 will operate in succession, tode-energize the brake disc 7 thereby interrupting the brake effectbetween the clutch disc 1 and the brake disc 7. At the same time, thecontrol relay 2'7 will close again the energizing circuit (VII) for themagnetic disc 4.

Since the circuit for the magnetic disc 4 includes the regulatableresistor 39, and therefore the voltage available for the circuit issmaller than under normal circumstances, the slippage between themagnetic disc d and the clutch disc will be increased, so that thesewing ma.- chine will run at reduced speed. If during that operationalphase either the contact 47 (or the contact d8) of the switch 42, whichis controlled automatically by the sewing machine, is opened, thecontrol relay 27 will be de-energized, the magnetic disc 4 will likewisebe de-ener gized and the brake disc 7 will again be energized.Accordingly, the sewing machine will be arrested in a predeterminedposition of the needle bar, since the switch 42 is controlled by partsof the sewing machine positively driven by the sewing machine itself.

The diagram of Fig. 3 utilizes a directly coupled motor 53 for drivingthe sewing machine. The motor 53 may be a series wound motor or a shuntmotor. The energizing circuit for the motor 53 is as follows:

(VIII) Electric circuit for energizing the motor 53 An alteratingcurrent network is tapped at the terminals llltl and 112 thereof. A lead191 connects the terminal 100 with a terminal 102. A lead 103 connectsthe terminal 102 with aterminal 1%. A lead 1115 connects the terminal104 with a motor terminal 54. The winding and brushes of the motor 53carry the current from the terminal 54 to a motor terminal 55. A lead106 connects the motor terminal 55 with a terminal 12 of a starter 11'that extends between the terminal 12 and a second starter terminal 13.terminal 13 with a terminal 1118. A lead 109 connects the terminal 108with a terminal 110; and a lead 111 interconnects the terminals 110 and112, thereby completing the circuit for the motor 53.

The starter 11 may be designed as a carbon pressure regulatable resistoror-a variable coil resistor. By varying the resistance of the starter11, the rotatable speed of the motor 53 may be varied. The primarywinding of a transformer 64 is connected to the terminals 104 and 108 bymeans of leads 113 and 11 1, respectively. The

secondary winding of the transformer 64 supplies the electric energy forthe relays 13, 22 and 27, and for the switches 15, 42 and 49, which aresimilar to the corresponding parts of, correspondingly numbered in, thepreviously described embodiment of Fig. 2.

The motor 53 is provided with a mechanically acting brake 56, which issubject to the action of a relief magnet 57 for electrically relievingthe motor 53 from the braking action of the brake 56 when the magnet 57is energized. Electric energy is delivered to the magnet 57 throughconnecting terminals 58 and 59 thereof. A rectifier 63 is connected tothe terminals 1112 and 111 by means of leads 115 and 115, respectively.The rectifier 63 serves to supply the electric energy necessary'for themagnet 57 to de-activate the brake 56. Normally, the brake 56 acts tobrake the motor 53, and the braking action is interrupted when the brakeS6 is de-activated by energization of the magnet 57.

The-starter 11 has an operating lever in which is movable betweenpositions in one of which (shownin Fig. 3) it acts to close the switchand to interrupt the circuit (VIII) of the motor 53, so that the motor'53 will be braked by the brake 56. Closing of the switch 15 by thelever 14' completes the circuit for the time delay relay 18 asfollows:

A lead 107 connects the A (lX -Eleelrlc circuit for the time delayrelay18 (Fig. :3)

A lead 117 connects-the secondary winding of the transformer 64 with arectifier ,65. A lead 118 connects the rectifier 65 with a terminal 119.A lead 120 connects the terminal 112 with a terminal 211 of the windingof the time delay relay 18, the winding terminating at a second terminal19. A lead 121 connects the terminal 19with a first terminal of theswitch 15, and a lead 122 completes the circuit between the secondterminal 16 (X) Electric circuit for the control relay 27 (Fig. 3)

As previously mentioned, the leads 117 and 118 connect the terminal 119with the secondary winding of the transformer 64. A lead 124.connectsthe terminal 119 with a terminal 28 of the coil or winding of the relay27, said coil terminating at another terminal 29. A lead 125 connectsthe terminal 29 with a terminal 26. A movable contact 126 that iscarried by the armature of the auxiliary relay 22 interconnects theterminal 26 (in the position shown in Fig. 3) with an opposite, terminal25 that is connected to a terminal point 127. A lead 128 interconnectsthe terminal point 127 with the terminal 21. The movable contact 123 ofthe time delay relay 18, the lead 121, the switch 15, and the lead 122complete the circuit for the relay 27.

When this circuit for the control relay 27 is closed by the operation ofthe relay 18, the relay 27 will be energized and will close with itsmovable contact 36 the following holding circuit for the relay 27:

(XI) Electric holding circuit for the relay 27 (Fig. 3)

-As previously described, the terminal 119 is connected to the secondarywinding of the transformer 64 by means of the leads 117 and 118 whichare in series with the rectifier 65. The lead 124 connects the terminals119 and 28, and the winding of the relay 27 completes the connection tothe terminal 29. A lead 129 connects the terminal 29 with a terminal 46'of the control switch 42. Like in the previous embodiment of Fig. 2,there are two circuit branches for the control switch 42, either branchterminating in the selector switch 49, depending on the position towhich the switch 49 has been set by the operator. In the position of theswitch 49 set as shown in Fig. 3, the energized branch circuit includesthe switch contact 48 which bridges the terminals 44 and 46,.a lead 130which ends in a terminal 50, and the selector switch 49 in the positionset (Fig. 3) which connects the terminal 50 with a terminal 52.

If the selector switch 49 is moved into the opposite position (not shownin Fig. 3), the connection between the terminals 46' and 52 will be theterminal 43, the contact 47, the terminal 45, a lead 131, the terminal51, the switch 42 and the terminal 52.

A lead 132 connects the terminal 52 with the terminal 37, and thecontact 36 of the relay 27 in this position (not shown in Fig. 3) ofenergization of the relay 27 bridges the gap between the contacts 37 and38. A lead 133 connects the terminal 38 with a terminal 25' that isdisposed adjacent a contact 144 carried by the armature of the auxiliaryrelay 22. The terminal 25 is interconnected to the terminal 127. Thelead 123 connects the terminal 25' with the terminal 21, and thecontact-123, the lead 121, the switch 15, and the lead 122 complete thecircuit terminating in the secondary winding of the transformer 64.

When the control relay 27 is operated, .its contact 31 will bridge thegap between the terminals 30 and 32, thereby closing the circuit for themagnet 57 to disengage the brake 56 from the motor 53, as follows:

(XII) Electric circuit for the brake relief magnet 57 (Fig. 3)

A lead 135 connects a terminal 134 of the rectifier 63 with the terminal59 of the magnet 57. A lead 136 connects the other terminal 58 of themagnet 57 with the terminal 30 of the relay 27. The movable contact 31of the relay 27 interconnects the terminals 30 and 32, and a lead 137connects the terminal 32 with a terminal 138 of the rectifier 63.

The auxiliary relay 22 is energized by a circuit that is completed bythe movable contact 33 of the control relay 27, as follows:

(XIII) Electric circuit for the auxiliary relay 22 (Fig. 3)

As previously described, the terminal 119 is interconnected to thesecondary winding of the transformer 64 by the leads 117 and 118 inseries with the rectifier 65. A lead 139 connects the terminal 119 witha terminal of the winding of the auxiliary relay 22 that terminates inanother terminal 23. A lead 140 connects the terminal 23 with a terminal141, and a lead 142 connects the terminal 141 with the terminal 34 nearthe relay 27. The movable contact 33 of the relay 27 will, when therelay 27 is energized, bridge the gap between the terminal 34 and aterminal 35 opposite thereto. A lead 143 connects the terminal 35 withthe terminal 127, and the lead 128, the contact 123 of the relay 18, thelead 121, the switch and the lead 122 complete the circuit.

The auxiliary relay 22, when thus energized, interrupts with its contact126 the circuit (X) for the control relay 27, and its contact 144bridges the gap between the terminal and a terminal 26', therebycompleting a holding circuit as follows:

(XIV) Electric holding circuit for the auxiliary relay 22 (Fig. 3)

As previously described, the terminal 141 is connected to the secondarywinding of the transformer 64, by means of elements including the leads117, 118, 139 and 140. A lead 145 interconnects the terminals 141 and26. The movable contact 144 will, when the auxiliary relay 22 isenergized interconnect the terminal 26 with the terminal 25. Theterminal 127 is connected to the terminal 25' and the circuit iscompleted to the secondary winding of the transformer 64 by means of thepreviously described elements which include the lead 128, the contact123, the lead 121, the switch 15, and the lead 122.

There is provided a switch 60 for the brake 56 which will be closedfollowing the disengagement of the brake 56 upon energization of thecircuit (XII) for the electromagnet 57. Closing of the switch 60 willclose a circuit for reactivating the motor 53 as follows:

(XV) Electric circuit for reactivation of the motor 53 As previouslydescribed, the terminal 12 of the starter 11' is interconnected to thenetwork terminal 100 by means of elements including the lead 106, thewinding of the motor 53, and the leads 105, 103 and 101. A lead 146connects a part of the starter 11' which is connected to the terminal 12to a terminal 62 of the switch 60. In Fig. 3, the switch 60 is shownopen. When it is closed, owing to the energization of the winding of themagnet 57, the gap between the terminal 62 and an opposite terminal 61is closed. A lead 145 connects the terminal 61 to the terminal 13, andas previously described, the terminal 13 is connected to the networkterminal 112 by means of the leads 107, 109 and 111.

Depending on the degree of resistance to which the starter 11' has beenset, the motor 53 will continue to turn at reduced rotatable speeduntil, as previously disclosed, one of the contacts 47 or 48 which is inserieswith the selector switch 49 is opened, thus interrupting theholding circuit (XI) of the control relay 27. Thereupon, the relay 27will be de-energized and the movable contact 36 of its armature willinterrupt the connection between the terminals 37 and 38, therebydiscontinuing the holding circuit (XI) of the relay 27 whichhaspreviously been interrupted. At the same time the contact 31 willinterrupt the circuit (XII) of the magnet 57, thereby permitting thebrake 56 to return into its active braking position and the motor 53will be braked.

In order to start the motor 53 again, the operator will move the lever14 of the starter 11' to the right (in Fig. 3) to restablish the motorcircuit (VIII). By this rightward movement, the switch 15 will be openedand there will be interrupted the circuit for the other relays, so thatall of the relays will be de-energized.

The operation of the embodiment of Fig. 3 is as follows:

To energize the motor 53, the operator will move the lever 14' of thestarter 11' to the right (Fig. 3), to close the motor circuit (VIII).The rotary speed of the motor 53 will depend on the resistance of thestarter 11 in the circuit.

In order to arrest the machine, on the other hand, the operator willmove the lever 14 to the left (Fig. 3) so that the increase of theresistance within the circuit will reduce the rotary speed of the motor53 until finally the circuit is interrupted. At this instant the motor53 will be braked mechanically by the brake 56. At the same time, thelever 14' will close the switch 15, thereby energizing the electriccircuit for the time delay relay (IX). After the passage of theretarding period for the relay, the brake 56 will be releasedelectromechanically, and the motor 53 will again, by means of the switch60, be connected to the network terminals and 112. In this position,however, a portion of the starter 11' resistance is within theenergizing circuit (XV) so that the rotary speed of the motor 53 isreduced. The switch 42 which is controlled mechanically from the sewingmachine, will open alternatively for each full turn of the sewingmachine shaft one of the contacts 47 or 48. As soon as the contact 48,which is in series with the switch 49, is opened, the holding circuit ofthe control relay 27 will be interrupted (in a manner similar to theafore described embodiment of Fig. 2) and the magnet 57 of the brake 56will be tie-energized so that the motor 53 is arrested.

After a new work piece has been inserted, the operator can initiate thenext full cycle in the same way as described in the foregoing.

The invention is not confined to the use of any definite number ofrelays. Although in the two arrangements shown by way of example theproblem of the relays has also been solved with the aid of three relays,it is within the frame of the invention to effect the switching operations by less than three, and even one alone. This is particularly sowhen smaller demands are imposed on the sensitiveness and exactness ofthe switching operations. Such single relay would then assume thefunctions of the control, retarding and implse-imparting auxiliaryrelays employed in the illustrated examples.

Although the invention is described with particular reference to thestopping of sewing machine parts it will be appreciated that it isequally applicable for use with other electrically driven machines, andthat in addition the particular arrangements described and illustratedherein are merely for the purpose of exemplifying the invention.

Having thus described the invention, What I claim as new and desire tobe secured by Letters Patent, is as follows:

1. A control system, for use in connection with a sewing machine havinga cyclically moving element, said control system being operable to stopthe sewing machine in apredetermined of a plurality .of certainpositions of saidiele ment in said cycle and comprisingan electriccontrol circuit including a plurality of parallel branches one foreachposition of said element and having in each branch a contact movable bysaid element in one of said certain positions and including a selectorswitch positionable in series with each parallel branch, drive means andbrake means for said sewing machine, an electric drive circuit operableto energize said drive means and including a variable regulator settableto control the degree of energization of said drive means and therebythe rotational speed of the sewing machine, an electric brake circuitoperable to energize said brake means, said control circuit including aswitch normally open, said regulator including means operable to closesaid switch when the drive means is energized by said regulator at lowvoltage and to open the switch when the drive means is energized atother voltages, and electric relay means energizable by said controlcircuit, said relay means being operable when energizedlfor renderingefiective said control circuit and said drive circuit and, respectively,when de-energized for interrupting said drive circuit and renderingeffective said brake means.

2. A control system as claimed in claim 1, said drive meansineluding acontinuously rotating electrically magnetizable disc and a coupling discjournalled adjacent said magnetizable disc and in driving connectionwith said sewing machine, said magnetizable disc being operable whenenergized to engage said coupling disc to rotateit, said brake meansincluding a stationary brake disc magnetizable by electric energizatio-nto brake said coupling disc, said relay means being operable whenenergized to energize said magnetizable disc for driving said couplingdisc, and said relay means being operable when de-energized fortie-energizing said magnetizable disc and for energizing said brake discto brake said coupling disc.

3. A control system as claimed in claim 1, said drive means including adirectly coupled motor driving said sewing machine, said brake meansincluding a mechanical brake normally positioned to brake said motor,said brake circuit including an electro-magnet operable for disengagingthe brake from the motor.

References Cited in the file of this patent UNITED STATES PATENTS2,440,849 Defandorf et al May 4, 1948 2,537,269 Harding Jan. 9, 19512,692,667 Bliedung et a1. Oct. 26, 1954 2,698,413 Thompson Dec. '28,1954 2,753,502 Kylin July 3, 1956

